[Xastir] IGATE

[wes at johnston.net]

You are right... never thought about it from an abuse standpoint.  I suppose I
never considered that more than one station would be sending a packet intended
for the same area... ie I am not satuating my local network on RF, and you
can't/don't saturate your local network on RF, but if each of us sends a packet
and it pop's out in atlanta along with 50 other people around the world who
wanna be seen in ATL, then the ATL network is plugged up and we don't even know
it.  That leads us right to a buffer to store a list of calls which have
recently been GATED to RF and should not be gated again for x seconds, or a
parm for a cap of max activity an IGATE can inject.  Boy does that add
complexity.  I suppose if a person wanted to control what their IGATE send out,
they could disable the airport designator name (or make it something obscure)
to limit traffic.  In that way, they could still operate as a "messages only"
igate w/o worry of floods from airport designator paths.

Given that we *can* do this w/o any additional buffers/counters, I cobbled up a
simple IF THEN around the IGATE function with a fixed callsign of SMS in it.  I
may play with it at home to see how it behaves.  Man, this is the WONDERFUL
thing... I can play and tweak and not depend on the Bros Sproul for yearly
updates.  All's I gotta do now is find how a variable name can be define in the
IGATE setup dialog box.

    // Check if airport designator is anywhere in path
   if (strstr(path,"SMS") == NULL) {     // added by wes one SMS is a variable,
we can test to see if it's a null value (ie blank) and bypass this test.

    // Check whether the source and destination calls have been
    // heard on local RF.
    if (!heard_via_tnc_in_past_hour(call)==1        // Haven't heard
destination call in previous hour
            || heard_via_tnc_in_past_hour(from)) {  // Have heard source call
in previous hour

        if (log_igate && (debug_level & 1024) ) {
            xastir_snprintf(temp,
                sizeof(temp),
                "IGATE NET->RF(%c):%s\n",
                third_party ? 'T':'N',
                line);
            log_data(LOGFILE_IGATE,temp);

        //  heard(call),  heard(from) : RF-to-RF talk
        // !heard(call),  heard(from) : Destination not heard on TNC
        // !heard(call), !heard(from) : Destination/source not heard on TNC

        if (!heard_via_tnc_in_past_hour(call))
            xastir_snprintf(temp,
                sizeof(temp),
                "REJECT: Destination not heard on TNC within an hour %s\n",
                call );
        else
            xastir_snprintf(temp,
                sizeof(temp),
                "REJECT: RF->RF talk\n");
            log_data(LOGFILE_IGATE,temp);
            fprintf(stderr,temp);
        }
        return;
    }
   }     // added by wes







On Fri, 18 Jul 2003 10:48:31 -0700 (PDT), "Curt Mills, WE7U" wrote:

> 
> On Fri, 18 Jul 2003 wes at johnston.net wrote:
> 
> > I think it's of interest b/c I want to have people back home track me when I
> > travel.  Yes, there is IGATE software which would allow me to ask the IGATE
> > operator to manually set it up, but I think it would be better if I could do
> it
> > myself.  It gives me the opportunity to effectively alter IGATES on the fly.
> >
> > As a 'fer instance... I was recently up in Roanoke VA for a month.  If I'd
> > wanted to track my buddy in south carolina, I could have asked in to put in
> the
> > airport designator for roanoke in his packet.  Likewise, I would have done
the
> > same and put in the designator for my home town.  Then we both appear
locally
> > on the other's 2m netowrks.
> 
> Note that this also takes a bunch of control away from the igate
> operator, plus opens up the system to potential abuses.  Not that
> I'm saying that'll occur, but everybody knows somebody who's
> somewhere else in the U.S./World.
> 
> If a small percentage of those do these cross-links and leave them
> that way, over time we'll get an awful lot of out-of-town traffic
> appearing on local RF, and there won't be an easy way to stop it.
> It could get to be a big pain as the igate operators are accosted by
> the local RF crowd and asked to reduce/eliminate these.  Either the
> function would be shut off, or each person sending the packets for
> some period of time would need to be asked directly to cease and
> desist.
> 
> I also see the good side of what you're trying to do.  I think it
> would be very useful if these problems can be addressed up-front.
> 
> -- 
> Curt Mills, WE7U                    hacker_NO_SPAM_ at tc.fluke.com
> Senior Methods Engineer/SysAdmin
> "Lotto:    A tax on people who are bad at math!"
> "Windows:  Microsoft's tax on computer illiterates!" -- WE7U
> "The world DOES revolve around me:  I picked the coordinate system!"

ham callsign: kd4rdb
find me: http://wesvan.zapto.org